It usually takes a hard heart and a strong stomach to sit through a play written by Adam Rapp. He’s as cynical as he is prolific, and as explicit as he is insightful. The yuck factor is always high in his work. Rape is a common occurrence. Blood is another. In the last decade alone, he’s shown Off Broadway theatergoers a self-administered surgery, the ravages of the plague, a guy enduring diarrhea, leach welts, vomiting, semen, and lots of male nudity. But the most you’ll see in Dreams of Flying Dreams of Falling is a bare butt skidding on a dining room table. Or, depending on where you’re sitting, Christine Lahti’s undies.

As I exited the show, I overheard a man say Dreams ”wasn’t as gross I expected.” And he’s right: It’s Adam Rapp lite. Even the subject matter is semisoft. Two rich, aging Yalies and their families gather for a dinner party to celebrate the release of one of the couples’ son from a mental institution. Beneath a crystal chandelier in a well-appointed room, they reveal their not-so-hidden nastiness — which ranges from making the African American maid perform for them to plotting murder with a vial of $25,000 poison. In truth, most of the monstrous behavior comes from a single character, matriarch Sandra (Christine Lahti, woefully miscast and painfully stumbling through her lines), who wears sparkly Chanel and likes to yell ”cock.” She’s purposefully oblivious to her daughter’s mental anguish, yet coddles her (illegal) pet barracuda. She relishes saying things like a goose was ”cooked in its own juices” and gleefully plans to serve perhaps the most inhumane creamy desert you can think of (I won’t spoil its contents here).

Yet, sadly, while Sandra (pronounced ”Sauuuundra”) is sort of shocking, there’s really nothing fresh or interesting about her. She comes from a long line of theater’s rich bitches — just as her friends and family, with all their woes, spring from our long-held need to believe that the wealthy hide secrets in their basements and mad women in their attics (both happen to be the case here). And of course, Rapp’s wealthy characters also ruin their children, destroy their marriages, and steal from you and me. It’s old hat and tiring — save for one comic scene in which the table is set while one pair make loud, wet love on top of it and a shocking final set-piece that does cut through your gut and up to your heart. Now that’s the Adam Rapp I know. B-